Yes. We're going to have a chat about humidity. If you live in a heating dominated, dry climate you might be thinking "what good is this for me to hear?" and I wouldn't blame you. But frankly, the more we know about humidity, the better we can understand how things work without it too. So dig in and think about how moisture affects the things we design and build. In this episode of The Building Science Podcast, we’ll explore the potential upside and downside of designing and building in humid climates.

If you're serious about building high performance homes in humid climates, you don't want to miss this year's Humid Climate Conference in Austin. Tickets are on sale now and we at The Building Science Podcast are thrilled to sponsor this year's conference. Don't miss it! The Humid Climate Conference is organized entirely by volunteers from the PHAUS (Passive House) Chapter in Austin with support from the national organization, PHIUS. 

What Is A Climate Zone?

“One of the fundamental principles of building science is that buildings must be suited to their climate. When they're not, problems can ensue. Maybe it's just that they're not as efficient as they should be. Maybe it's worse. Put plastic between the drywall and framing of your exterior walls in Ottawa, and it can help control vapor drive from the interior air and its associated moisture problems (rare in all but except in extremely cold climates). Put that plastic in the same place in Georgia, and you're going to rot the walls.

The first thing to know about climate zones is that we divide them up based on two parameters: temperature and moisture. The map at the top of this article, from Building Science Corporation, is one that seems to be in a lot of the curricula for home energy rater and other energy auditor classes. The fancy word for this type of division is hygrothermal, and Building Science Corp. has a nice interactive map of hygrothermal regions.

The map above divides all of North America into broad regions based on temperature and then humidity. The International Code Council has a more fine-grained approach to climate zones,† as shown below in the map of the US from the International Energy Conservation Code (IECC). Each zone has a number, starting with 1 for the hottest US climate, the southernmost tip of Florida, and going up to 8, the coldest parts in Alaska.”

-Dr. Allison Bailes, III

For more images mentioned in the episode, check out the show’s webpage.